PlatformTransactionManager
implementation for a single Hibernate SessionFactory.
Binds a Hibernate Session from the specified factory to the thread, potentially
allowing for one thread-bound Session per factory. SessionFactoryUtils
and HibernateTemplate are aware of thread-bound Sessions and participate
in such transactions automatically. Using either of those or going through
SessionFactory.getCurrentSession() is required for Hibernate
access code that needs to support this transaction handling mechanism.

Supports custom isolation levels, and timeouts that get applied as
Hibernate transaction timeouts.

This transaction manager is appropriate for applications that use a single
Hibernate SessionFactory for transactional data access, but it also supports
direct DataSource access within a transaction (i.e. plain JDBC code working
with the same DataSource). This allows for mixing services which access Hibernate
and services which use plain JDBC (without being aware of Hibernate)!
Application code needs to stick to the same simple Connection lookup pattern as
with DataSourceTransactionManager
(i.e. DataSourceUtils.getConnection(javax.sql.DataSource)
or going through a
TransactionAwareDataSourceProxy).

Note: To be able to register a DataSource's Connection for plain JDBC code,
this instance needs to be aware of the DataSource (setDataSource(javax.sql.DataSource)).
The given DataSource should obviously match the one used by the given
SessionFactory. To achieve this, configure both to the same JNDI DataSource,
or preferably create the SessionFactory with LocalSessionFactoryBean and
a local DataSource (which will be autodetected by this transaction manager).

JTA (usually through JtaTransactionManager)
is necessary for accessing multiple transactional resources within the same
transaction. The DataSource that Hibernate uses needs to be JTA-enabled in
such a scenario (see container setup). Normally, JTA setup for Hibernate is
somewhat container-specific due to the JTA TransactionManager lookup, required
for proper transactional handling of the SessionFactory-level read-write cache.

On JDBC 3.0, this transaction manager supports nested transactions via JDBC 3.0
Savepoints. The AbstractPlatformTransactionManager.setNestedTransactionAllowed(boolean) "nestedTransactionAllowed"}
flag defaults to "false", though, as nested transactions will just apply to the
JDBC Connection, not to the Hibernate Session and its cached objects. You can
manually set the flag to "true" if you want to use nested transactions for
JDBC access code which participates in Hibernate transactions (provided that
your JDBC driver supports Savepoints). Note that Hibernate itself does not
support nested transactions! Hence, do not expect Hibernate access code to
semantically participate in a nested transaction.

Set whether to prepare the underlying JDBC Connection of a transactional
Hibernate Session, that is, whether to apply a transaction-specific
isolation level and/or the transaction's read-only flag to the underlying
JDBC Connection.

getSessionFactory

setDataSource

Set the JDBC DataSource that this instance should manage transactions for.
The DataSource should match the one used by the Hibernate SessionFactory:
for example, you could specify the same JNDI DataSource for both.

If the SessionFactory was configured with LocalDataSourceConnectionProvider,
i.e. by Spring's LocalSessionFactoryBean with a specified "dataSource",
the DataSource will be auto-detected: You can still explictly specify the
DataSource, but you don't need to in this case.

A transactional JDBC Connection for this DataSource will be provided to
application code accessing this DataSource directly via DataSourceUtils
or JdbcTemplate. The Connection will be taken from the Hibernate Session.

The DataSource specified here should be the target DataSource to manage
transactions for, not a TransactionAwareDataSourceProxy. Only data access
code may work with TransactionAwareDataSourceProxy, while the transaction
manager needs to work on the underlying target DataSource. If there's
nevertheless a TransactionAwareDataSourceProxy passed in, it will be
unwrapped to extract its target DataSource.

setPrepareConnection

public void setPrepareConnection(boolean prepareConnection)

Set whether to prepare the underlying JDBC Connection of a transactional
Hibernate Session, that is, whether to apply a transaction-specific
isolation level and/or the transaction's read-only flag to the underlying
JDBC Connection.

Default is "true". If you turn this flag off, the transaction manager
will not support per-transaction isolation levels anymore. It will not
call Connection.setReadOnly(true) for read-only transactions
anymore either. If this flag is turned off, no cleanup of a JDBC Connection
is required after a transaction, since no Connection settings will get modified.

Default is "false", i.e. using a Spring-managed Session: taking the current
thread-bound Session if available (e.g. in an Open-Session-in-View scenario),
creating a new Session for the current transaction otherwise.

Switch this flag to "true" in order to enforce use of a Hibernate-managed Session.
Note that this requires SessionFactory.getCurrentSession()
to always return a proper Session when called for a Spring-managed transaction;
transaction begin will fail if the getCurrentSession() call fails.

This mode will typically be used in combination with a custom Hibernate
CurrentSessionContext implementation that stores
Sessions in a place other than Spring's TransactionSynchronizationManager.
It may also be used in combination with Spring's Open-Session-in-View support
(using Spring's default SpringSessionContext), in which case it subtly
differs from the Spring-managed Session mode: The pre-bound Session will not
receive a clear() call (on rollback) or a disconnect()
call (on transaction completion) in such a scenario; this is rather left up
to a custom CurrentSessionContext implementation (if desired).

setEarlyFlushBeforeCommit

public void setEarlyFlushBeforeCommit(boolean earlyFlushBeforeCommit)

Set whether to perform an early flush before proceeding with a commit.

Default is "false", performing an implicit flush as part of the actual
commit step. Switch this to "true" in order to enforce an explicit early
flush right before the actual commit step.

An early flush happens before the before-commit synchronization phase,
making flushed state visible to beforeCommit callbacks of registered
TransactionSynchronization
objects. Such explicit flush behavior is consistent with Spring-driven
flushing in a JTA transaction environment, so may also get enforced for
consistency with JTA transaction behavior.

setEntityInterceptorBeanName

Set the bean name of a Hibernate entity interceptor that allows to inspect
and change property values before writing to and reading from the database.
Will get applied to any new Session created by this transaction manager.

Requires the bean factory to be known, to be able to resolve the bean
name to an interceptor instance on session creation. Typically used for
prototype interceptors, i.e. a new interceptor instance per session.

Can also be used for shared interceptor instances, but it is recommended
to set the interceptor reference directly in such a scenario.

Parameters:

entityInterceptorBeanName - the name of the entity interceptor in
the bean factory

setEntityInterceptor

Set a Hibernate entity interceptor that allows to inspect and change
property values before writing to and reading from the database.
Will get applied to any new Session created by this transaction manager.

Such an interceptor can either be set at the SessionFactory level,
i.e. on LocalSessionFactoryBean, or at the Session level, i.e. on
HibernateTemplate, HibernateInterceptor, and HibernateTransactionManager.
It's preferable to set it on LocalSessionFactoryBean or HibernateTransactionManager
to avoid repeated configuration and guarantee consistent behavior in transactions.

setJdbcExceptionTranslator

Applied to any SQLException root cause of a Hibernate JDBCException that
is thrown on flush, overriding Hibernate's default SQLException translation
(which is based on Hibernate's Dialect for a specific target database).

doGetTransaction

The returned object will usually be specific to the concrete transaction
manager implementation, carrying corresponding transaction state in a
modifiable fashion. This object will be passed into the other template
methods (e.g. doBegin and doCommit), either directly or as part of a
DefaultTransactionStatus instance.

The returned object should contain information about any existing
transaction, that is, a transaction that has already started before the
current getTransaction call on the transaction manager.
Consequently, a doGetTransaction implementation will usually
look for an existing transaction and store corresponding state in the
returned transaction object.

isExistingTransaction

Check if the given transaction object indicates an existing transaction
(that is, a transaction which has already started).

The result will be evaluated according to the specified propagation
behavior for the new transaction. An existing transaction might get
suspended (in case of PROPAGATION_REQUIRES_NEW), or the new transaction
might participate in the existing one (in case of PROPAGATION_REQUIRED).

The default implementation returns false, assuming that
participating in existing transactions is generally not supported.
Subclasses are of course encouraged to provide such support.

doBegin

Begin a new transaction with semantics according to the given transaction
definition. Does not have to care about applying the propagation behavior,
as this has already been handled by this abstract manager.

This method gets called when the transaction manager has decided to actually
start a new transaction. Either there wasn't any transaction before, or the
previous transaction has been suspended.

A special scenario is a nested transaction without savepoint: If
useSavepointForNestedTransaction() returns "false", this method
will be called to start a nested transaction when necessary. In such a context,
there will be an active transaction: The implementation of this method has
to detect this and start an appropriate nested transaction.

doCommit

An implementation does not need to check the "new transaction" flag
or the rollback-only flag; this will already have been handled before.
Usually, a straight commit will be performed on the transaction object
contained in the passed-in status.

doRollback

An implementation does not need to check the "new transaction" flag;
this will already have been handled before. Usually, a straight rollback
will be performed on the transaction object contained in the passed-in status.

doSetRollbackOnly

Set the given transaction rollback-only. Only called on rollback
if the current transaction participates in an existing one.

The default implementation throws an IllegalTransactionStateException,
assuming that participating in existing transactions is generally not
supported. Subclasses are of course encouraged to provide such support.

isSameConnectionForEntireSession

Return whether the given Hibernate Session will always hold the same
JDBC Connection. This is used to check whether the transaction manager
can safely prepare and clean up the JDBC Connection used for a transaction.